160159-29-5Relevant academic research and scientific papers
Conformational Isomers of Bis(tert-butylphosphine)osmium Complexes
Daniel, Thomas,Werner, Helmut
, p. 221 - 228 (1994)
Reaction of with Na in methanol, in presence of KPF6, afforded the oximato compound 2-ON=CMe2)(PMe(t-Bu)2)>PF6 which on further reaction with HN=CPh2 gave the azavinylidene complex PF6.By using a similar synthetic route, the bis(tert-butylphosphine)osmium(II) derivatives , 2-ON=CMe2)(PH(t-Bu)2)>PF6 and PF6 (arene = C6H6 or C6H3Me3-1,3,5; X = Cl or I) were obtained, in most cases almost quantitatively.The NMR spectra of all the latter complexes and of 2-ON=CMe2)(PMe(t-Bu)2)>PF6 are temperature-dependent and thus indicative of a dynamic behaviour in solution.The most reasonable explanation for these observations is that due to a hindered rotation around the Os-P axis conformational isomers are formed.The energy barrier for the conversion significantly depends on the type of the non-phosphine ligands co-ordinated to osmium and is, for arene = C6H6, in PF6 higher than in and in the mesitylene complexes higher than in the benzene derivatives.For PF6, a value of ΔG(excit.) for the rotational barrier of ca. 60 kJ mol-1 has been calculated.
